Neoprene - It's soft, elastic, lightweight, breathable, resistant, and has many excellent qualities that make it ideal for heavy lifting!
Cotton stitching - Strong, comfortable and durable. This stitching is never going to quit. Just like yourself! Feel safe pushing it to the extreme knowing these knee sleeves will keep up. 
Cotton Band - Hey just because you lift, doesn’t mean you can’t be comfortable! Soft cotton straps at the top and bottom maximize comfort levels while you push your comfort zone!